EFFECT OF MATERNAL VITAMIN B-6 DEFICIENCY ON CERTAIN NEUROTRANSMITTER AND AMINO ACID LEVELS AND ON SYNAPSE FORMATION IN SPECIFIC REGIONS OF DEVELOPING BRAIN IN PROGENY
Abstract
The effects of maternal vitamin B-6 deficiency on concentrations of the neurotransmitters, (gamma)-aminobutyric acid (GABA) and dopamine (DA), and sixteen amino acids in specific regions, substantia nigra (SN), caudate/putamen (C/P), cortex (CORT), were studied in 15-day-old progeny. These measurements were examined in relation to synapse counts and neuronal density in C/P of progeny. Two strains of female rats, Wistar (group I) and Sprague-Dawley (group II), were fed either a deficient (0.6 mg pyridoxine(.)HCl (PN(.)HCl) diet) or control (7.0 mg PN(.)HCl/kg diet) diet from weaning throughout gestation and lactation. Analyses of brain regions of progeny were made at 15 days of age generally after gross neurological symptoms appeared in deficient groups. Biochemical alterations observed in the deficient animals included increased concentrations of cystathionine, glycine, methionine, phenylalanine, leucine, isoleucine and valine and decreased concentrations of alanine and serine in all brain regions studied (SN, C/P, CORT) and with some noticeable regional differences. GABA concentrations were decreased in C/P of deficient animals from group I compared to control values whereas concentrations of aspartic acid, glutamic acid or DA were not affected by the deficiency in any region studied. At 1 hr following an intraperitoneal injection of PN(.)HCl into deficient progeny, a significant decrease was observed in glutamic acid in C/P and a significant increase of aspartic acid in SN. Additionally, GABA levels were increased significantly in SN within 3 hr post-injection. Since glutamic acid is a precursor of both aspartic acid and GABA, these findings indicated the involvement of vitamin B-6 in strionigral connections. Following PN(.)HCl injection increased GABA concentrations in SN may compensate for the significant increases of DA observed in C/P at 1 and 3-hr post-injection. Morphological changes associated with the biochemical changes included decreased numbers of synapses and increased neuronal density in C/P of deficient pups compared to control values.
Degree
Ph.D.
Subject Area
Nutrition
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